What could the problem be?

KPELLICCIO

MEMBER
2002 SATURN L300
151,000 MILES

I went to Advance Auto to get them to read my check engine light and they told me the codes were a misfire and for a speed sensor. I changed my spark plugs and coils and also the speed sensor, but my car still idles very rough. Sometimes it will idle great, other times it will be very rough and my RPMs will constantly be moving while I'm sitting. Any ideas on what else it could be?

5 Replies

SATURNTECH9

MECHANIC
30,869 POSTS

So what codes do you have now?I need the exact code numbers not the code descriptions.

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Tuesday, August 30th, 2011 AT 12:06 AM

KPELLICCIO

MEMBER
3 POSTS

The code it is saying now is P0300.

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Tuesday, August 30th, 2011 AT 12:55 AM

SATURNTECH9

MECHANIC
30,869 POSTS

So what were code nunbers did you had before the repairs?So it has a random misfire only sometimes?Is the misfire only at idle or also while driving down the road?

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Tuesday, August 30th, 2011 AT 1:00 AM

KPELLICCIO

MEMBER
3 POSTS

Im not sure of the exact codes, I know they were numbers around 302, 303 etc. And then 503 for my speed sensor, which it is no longer reading off. And yes, its only sometimes. It will only do it when im idling, but it wont do it everytime. Once I accelerate it is perfectly fine, but will start again when im stopped anywhere. But I can re start my car and then itll work fine.

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Tuesday, August 30th, 2011 AT 2:16 AM

SATURNTECH9